Re: Awesome ISS photos!!!

From: Bjoern Gimle (b_gimle@algonet.se)
Date: Tue Jun 12 2001 - 10:15:47 PDT

  • Next message: Anthony Ayiomamitis: "Re: Re: Awesome ISS photos!!!"

    > > Did you use camera with film before? (Someone mentioned that recently)
    >
    > I have done lots of astrophotography with film before ... lunar cycle,
    eclipses,
    > features ....
    >
    I meant to capture satellites transitting the moon (or just black space)
    
    ...
    > > short time on each one. Have you tried your setup without the moon being
    in
    >
    > My only other attempts without the moon have involved the ISS which I have
    > captured successfully ... there is also the iridium flares but those are a
    > different beast ...
    >
    > > the area? What is the magnitude limit for satellite photography with
    > > comparable angular speed?
    >
    > This is something I have no idea ...
    
    I meant you should try to see that your setup has a CHANCE of imaging a
    satellite passing the Moon.
    >
    > > As for dark satellites silhouetted against a bright(er) moon, it needs
    very
    > > high contrast, and I can not imagine it being photographed, because the
    > > satellite obscures such a small area for a short (?) interval on each
    frame.
    >
    > My philosophy here (and this is where my failed attempts are concentrated)
    is
    > that with a 1- to 2-second pass across the lunar surface, there should be
    ample
    > time for acquisition and photography. The transit on Thursday is good in
    the
    > sense that the transitting satellite (mag +4.8) which travel across both
    the
    > dark and illuminated parts which is an opportunity for training my eye on
    what
    > to expect across the two types of backgrounds.
    >
    But the eye is different from film and CCD. If you have 600 pixels across
    the Moon, each one is roughly 6*6 km.
    At 750 km range, that is 12*12 m. So, even if the satellite has an effective
    albedo five times the Moon's, it would need 28 sq.m. to match its intensity.
    And a dark satellite of 6*6 m would only remove ~25% of the Moon's light
    during 1/600 s. - how long is your camera's exposure time/frame ?
    
    
    
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